[1] Born in Luxembourg City on 23 January 1949, Mullenbach studied piano, chamber music and composition at the Conservatoire de Paris and at the Salzburg Mozarteum, where his teachers included Gerhard Wimberger and Cesar Bresgen.
[2] Performers have included Heinrich Schiff, Boris Pergamenschikow, Marjana Lipovšek, Roberto Fabbriciani, Julius Berger, Alois Brandhofer, Irena Grafenauer, Elliot Fisk, Kurt Widmer, Edoardo Catemario, Tsuyoshi Tsutsumi, Christina Ortiz, Ruggiero Ricci, Roberto Szidon, Edda Silvestri, Gottfried Schneider, Lewis Kaplan, Yair Kless, Frank Wibaut, Antonello Farulli, Frederico Mondelci, Maria Christina Kiehr, Yoko Amoyal, Elena Denisova, Velislava Georgieva, Françoise Groben, Michael Vaiman, Frank Stadler, Iride Martinez, and the ensembles Wiener Streichsextett, Hagen Quartett, Atlas Quartett, Stadler Quartett, Camerata Salzburg, Musica Viva Dresden, Alter Ego Rome, Atelier Musique Nouvelle de Paris, Klangforum Wien, Österreichisches Ensemble für Neue Musik, Wiener Kammerorchester, Philharmonische Virtuosen Berlin, Parnassus Ensemble London, Mozarteum Quartett Salzburg, Vilnius-Quartett, Pierrot Lunaire Ensemble Vienna, Mozarteum Orchester Salzburg; Orchestre Philharmonique du Luxembourg, Rheinische Philharmonie Koblenz, Orchestre de Chambre du Luxembourg"Les Musiciens", Kammerakademie Neuss/Rhein.
Conductors who have directed his symphonic works include Ernest Bour, Leopold Hager, Hans Graf and Udo Zimmermann, David Shallon, Stanislaw Skrowaczewski, Philippe Entremont, Hubert Soudant, Hans Graf, Günter Neuhold, Antoni Wit, Emmanuel Krivine, Daniel Raiskin, Jari Hämälainen, Jaap Schroeder, Pierre Cao, Johannes Kalitzke, Marc Soustrot, Sylvain Cambreling.
In 2015, he received the title of Doctor Honoris Causa from University of Music “Academie Gheorghe Dima” Cluj in Romania.
Several CD publications, among them: Alexander Müllenbach – Wie Haar, das über Steine rinnt und andere Kammermusik (5 450482 001265) CNA Dudelange-Luxembourg © by United Instruments of Lucilin